1. Fields of Invention
The present invention relates to a traffic light invention, and, more particularly, relates to a Light Emitting Diode (LED) traffic light apparatus and corresponding methods of manufacture and use thereof.
2. Discussion Of Background And Prior Art
The typical conventional traffic light has a heavy housing unit which holds a vertical or horizontal arrangement of at least three different round signal lights each having a corresponding lens (See FIG. 1--Prior Art). The three round lights are a red signal light which represents "Stop", a yellow signal light which represents "Caution", and a green signal light which represents "Go". A red arrow signal light and/or a green arrow signal light, which are used for controlling protected turns, can also be added to the arrangement. In the conventional arrangement, the red signal light is produced by using an incandescent bulb (i.e. typically 67 to 150 watts) and a red filter. Similarly, the yellow signal light is produced by using an incandescent bulb and a yellow filter, and the green signal light is produced by using an incandescent bulb and a green filter. Furthermore, the red arrow signal light is produced by using an incandescent bulb and a filter that produces a red arrow, and the green arrow signal light is produced by using an incandescent bulb and a filter that produces a green arrow.
Each incandescent lamp (i.e. single round light or single arrow light) used in the typical traffic light consumes a fair amount of power (i.e. about sixty seven (67) to one hundred fifty (150) watts) in relative to a number of other types of light bulbs or light sources. Incandescent lamps have the disadvantage of producing a lot of heat when they are being used, and they do not produce useful light efficiently (i.e. only a small amount of light produced by incandescent lamps is in the visible spectrum). For example, only the red light of the incandescent lamp passes through the red filter lens and is used to provide the red signal light for a traffic light. Therefore, a lot of energy is wasted in producing the rest of the light and heat.
Furthermore, the incandescent lamps burn out and have to be replaced periodically (i.e. at least annually to conform with the National Traffic Safety Board regulations). Since the replacement of the bulbs for the incandescent lamps has to be done on site (i.e. at the intersection), a crew is usually necessary to perform this task. Therefore, the costs of replacing the incandescent lamp parts themselves and the personnel and labor required to perform these replacing services add to the costs of using and maintaining incandescent lamps for traffic lights.
Therefore, Light Emitting Diodes (LEDs) are being experimented with and used to replace incandescent lamps for traffic lights (See disclosure in Tech Update by E Source, November 1995, pp. 1-16 and Chapter 13 of E Source Publication, Secs. 13.1 to 13.2.2, 1994). The LED traffic light would also include the vertical or horizontal arrangement of at least three round signal lights (i.e. red, yellow, green) and can also include the protected turn signal (i.e. red arrow, green arrow) (See FIG. 2--Prior Art). Each of the signal lights includes a number of LEDs closely arranged together in the desired round or arrow pattern. The LED traffic light provides the advantages of generally consuming less power (i.e. single round light or single arrow light consumes about nine (9) to twenty five (25) watts of power), of producing at least red light (i.e. red signal light) more efficiently and very cost effectively, and of not burning out as often as an incandescent light. However, red light producing LEDs are designed only to provide red light, and they cannot be filtered to produce other colors.
LEDs can be changed to produce other colors by changing the ratios of various trace elements. Thus, yellow (amber) and green LEDs are available. Furthermore, the conventional traffic light design has been used for the LED traffic light (i.e. at least three different round signal lights each having a lens), and therefore, the typical heavy and bulky housing is still used to hold the round or arrow patterned LED traffic signal lights. Therefore, the costs and problems associated with providing, mounting, and maintaining the typical housing still exist. Heavy duty equipment (i.e. cables or poles) is still needed to hold and maintain the LED traffic light, and necessary personnel are needed to mount the LED traffic light.
Furthermore, the conventional LED traffic light still has the problem of allowing a driver or pedestrian to distinguish one light from the other only by its position on the three (3) light array. This problem is especially evident for persons that are color blind who may not be able to easily distinguish one color light from the other.
Therefore, an LED traffic light invention that is overall more efficient and cost effective, that has a less bulky, less expensive, and easy to mount housing unit, and that is designed so that each of the lights is more easily distinguishable is needed and desired, and it is an object of the present invention to overcome the problems and limitations of the prior art that has been discussed.